Coptis chinensis, and extracts of guava and mulberry leaves present good inhibiting potential on obesity and associated metabolic disorders in high-fat diet obesity mice model

Abstract

This study aimed to investigate the anti-obesity effects of Coptis chinensis (CC), BALASAN (combinational guava leaf extract and mulberry leaf extract), and CC/BALASAN (CC/BAL) on high-fat diet-induced obese C57BL/6 mice and to explore possible mediating mechanisms in 3T3-L1 pre-adipocytes. Oil red-O stain was used to test the effects of CC, BALASAN, and CC/BAL on the differentiation of 3T3-L1 pre-adipocytes. Additionally, real-time PCR was used to detect the expression of genes involved in adipocyte differentiation and inflammation-related genes in adipose tissue of mice that were fed a high-fat diet. CC, BALASAN, and CC/BAL inhibited the differentiation of 3T3-L1 pre-adipocytes and exhibited excellent inhibitory ability against the expression of PPARγ and RXRα genes associated with adipocyte differentiation. Replenishing mice with a high-fat diet with CC, BALASAN, and CC/BAL reduced body weight gaining and blood glucose and plasma cholesterol levels. CC also effectively reduced liver weight, whereas BALASAN and CC/BAL had no inhibitory effect. In addition, CC effectively inhibited the expression of C/EBP-α in adipose tissue. Interestingly, BALASAN not only inhibited the expression of C/EBP-α, but also that of PPARγ, RXRα, and TNFα. Such data indicated that CC, BALASAN, and CC/BAL may have potentially beneficial effects against obesity and associated metabolic disorders by down-regulating the PPARγ/RXRα pathway.

Keywords: 3T3-L1 pre-adipocytes; Adipocyte differentiation genes; Anti-inflammation; Anti-obesity; BALASAN; Coptis chinensis.

Graphical abstract

Fig. 1

Effect of CC, BALASAN, and CC/BAL on adipocyte differentiation of 3T3-L1 pre-adipocytes. 3T3-L1 pre-adipocytes were differentiated into adipocytes in the absence or presence of CC, BALASAN, and CC/BAL for 8 days. Intracellular lipid of CC (A), BALASAN (B), and CC (50 μg/ml)/BAL (50 μg/ml) (C) was determined using Oil Red O stain. The amount of Oil Red O was quantified after extraction with isopropanol. Data are (means ± SEM) calculated from three independent experiments for each treatment.

Fig. 2

Effect of CC, BALASAN, and CC/BAL on mRNA levels of PPARγ, SREBP-1c, and RXRα. 3T3-L1 preadipocytes were differentiated into adipocytes in medium with or without CC, BALASAN, and CC/BAL for 8 days. The expression mRNA levels of (A) PPARγ, (B) SREBP-1c, and (C) RXRα were determined by real-time quantitative RT-PCR. The expression of GAPDH mRNA was used as internal control for the real-time quantitative RT-PCR. Data are represented as mean ± SEM of four independent experiments.

Fig. 3

Effects of CC, BALASAN, and CC/BAL on body weight in male C57BL/6J mice fed a high-fat diet for 8 weeks. All mice were divided into four groups (control group, n = 3; CC group, n = 3; BALASAN group, n = 5; CC/BAL group, n = 3), and allowed free access to high-fat feed and water for 8 weeks. Control group HFD exhibited a significantly greater weight gain on average compared with all other groups. Data are means ± SEMs (n = 3–5). ∗p < 0.05，∗∗p < 0.01.

Fig. 4

Effects of CC, BALASAN and CC/BAL on liver weight and blood biochemical change. During the 8 weeks on individual treatments, all groups were exposed to high fat diet. Liver weight (A) was normalized to body weight. While, blood glucose (B) and total cholesterol (C) were determined by blood glucose meter and cholesterol assay kit. Data are means ± SEMs (n = 3–5).

Fig. 5

Effects of CC, BALASAN, and CC/BAL on mRNA levels of C/EBP-α, C/EBP-β, PPARγ, RXRα, FAS, ACS, TNFα, IL-6, and IL-1βin adipose tissue from HFD-treated mice. During the 8 weeks on individual treatments, all groups received a high-fat diet. The mRNA levels of C/EBP-α, C/EBP-β, PPARγ, RXRα, FAS, ACS, TNFα, IL-6, and IL-1β from adipose tissue were determined by real time PCR. Data are means ± SEMs (n = 3–5).